docs: def fun_as_arg(self, x, *args):
          """``fun_as_arg(x, fun, *more_args)`` calls ``fun(x, *more_args)``.
  
          Use case::
  
              fmin(cma.fun_as_arg, args=(fun,), gradf=grad_numerical)
  
          calls fun_as_args(x, args) and grad_numerical(x, fun, args=args)
  
          """
          fun = args[0]
          more_args = args[1:] if len(args) > 1 else ()
          return fun(x, *more_args)